Fluorination of the n = 2 Ruddlesden–Popper oxide, La3Ni2O7, with polyvinylidene fluoride yields La3Ni2O5F4, a phase in which fluoride ions have been inserted into interstitial sites in the Ruddlesden–Popper framework and also exchanged with the oxide ions residing on apical anion sites. Reaction with LiH at 190 °C reduces La3Ni2O5F4 by extracting interstitial fluoride ions. The resulting phase, La3Ni2O5F3, adopts a structure described in space group Pbcm in which the fluoride ions in the half-filled interstitial layer are arranged in chains parallel to the y-axis, and the NiO5F octahedra adopt an a–a–c+/–(a–a–)c+ tilting pattern. Further reduction with LiH at 250 °C converts La3Ni2O5F3 into La3Ni2O5F, a Ni1+ phase which adopts a T′-structure consisting of double infinite-sheets of apex linked NiO4 squares, stacked with LaOF fluorite-type layers. Magnetization and neutron diffraction data indicate La3Ni2O5F3 adopts an antiferromagnetically ordered state below TN = 225 K, while magnetization data from La3Ni2O5F exhibit a broad maximum centered at 75 K, suggestive of antiferromagnetic order.
n = 2 Ruddlesden-Popper氧化物La3Ni2O7与聚偏氟乙烯氟化反应生成La3Ni2O5F4，其中氟离子被插入Ruddlesden-Popper骨架的间隙位置，并与位于顶端阴离子位置的氧化物离子交换。与LiH在190℃下反应，通过提取间隙氟离子还原La3Ni2O5F4。所得相La3Ni2O5F3采用Pbcm空间基描述的结构，其中半填充的间隙层中的氟离子呈平行于y轴的链排列，NiO5F八面体呈a -a - c+/ - (a -a -)c+倾斜模式。在250℃下用LiH进一步还原，La3Ni2O5F3转化为La3Ni2O5F，这是一种Ni1+相，采用T '型结构，由双无限大的顶端连接的NiO4方形片组成，并堆叠有LaOF萤石型层。磁化和中子衍射数据表明，La3Ni2O5F3在TN = 225 K以下为反铁磁有序态，而La3Ni2O5F的磁化数据显示，在75 K处，La3Ni2O5F3为反铁磁有序态。
{"title":"Synthesis of the Double Infinite-Layer Ni(I) Phase La3Ni2O5F via Sequential Topochemical Reactions","authors":"Romain Wernert,Robert D. Smyth,Michael A. Hayward","doi":"10.1021/jacs.5c16740","DOIUrl":"https://doi.org/10.1021/jacs.5c16740","url":null,"abstract":"Fluorination of the n = 2 Ruddlesden–Popper oxide, La3Ni2O7, with polyvinylidene fluoride yields La3Ni2O5F4, a phase in which fluoride ions have been inserted into interstitial sites in the Ruddlesden–Popper framework and also exchanged with the oxide ions residing on apical anion sites. Reaction with LiH at 190 °C reduces La3Ni2O5F4 by extracting interstitial fluoride ions. The resulting phase, La3Ni2O5F3, adopts a structure described in space group Pbcm in which the fluoride ions in the half-filled interstitial layer are arranged in chains parallel to the y-axis, and the NiO5F octahedra adopt an a–a–c+/–(a–a–)c+ tilting pattern. Further reduction with LiH at 250 °C converts La3Ni2O5F3 into La3Ni2O5F, a Ni1+ phase which adopts a T′-structure consisting of double infinite-sheets of apex linked NiO4 squares, stacked with LaOF fluorite-type layers. Magnetization and neutron diffraction data indicate La3Ni2O5F3 adopts an antiferromagnetically ordered state below TN = 225 K, while magnetization data from La3Ni2O5F exhibit a broad maximum centered at 75 K, suggestive of antiferromagnetic order.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"1 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146111261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Moritz Nau,Raka Ahmed,Susanne Leitherer,Gemma C. Solomon,Rainer F. Winter
The concept of aromaticity is one of the most fundamental principles for understanding the properties and reactivities of organic molecules. However, in molecular electronics research, it has been shown that aromaticity is not necessarily advantageous for electron transmission across electrode-molecule-electrode junctions. In this work, we introduce formally antiaromatic, yet planar N,N’-disubstituted dihydrophenazines as a compelling building block for exploring molecular conductance properties beyond the scope of classical aromatic molecules and compare anchor group-modified dihydrophenazines and structurally closely related anthracenes. We find that molecular conductance increases by 1.5 orders of magnitude from aromatic anthracenes to their phenazine congeners, where the central ring attains partially antiaromatic character. Oxidation of the dihydrophenazine core results accordingly in conductance attenuation.
{"title":"Oxidation of a Dihydrophenazine Molecular Wire Attenuates Molecular Conductance","authors":"Moritz Nau,Raka Ahmed,Susanne Leitherer,Gemma C. Solomon,Rainer F. Winter","doi":"10.1021/jacs.5c18249","DOIUrl":"https://doi.org/10.1021/jacs.5c18249","url":null,"abstract":"The concept of aromaticity is one of the most fundamental principles for understanding the properties and reactivities of organic molecules. However, in molecular electronics research, it has been shown that aromaticity is not necessarily advantageous for electron transmission across electrode-molecule-electrode junctions. In this work, we introduce formally antiaromatic, yet planar N,N’-disubstituted dihydrophenazines as a compelling building block for exploring molecular conductance properties beyond the scope of classical aromatic molecules and compare anchor group-modified dihydrophenazines and structurally closely related anthracenes. We find that molecular conductance increases by 1.5 orders of magnitude from aromatic anthracenes to their phenazine congeners, where the central ring attains partially antiaromatic character. Oxidation of the dihydrophenazine core results accordingly in conductance attenuation.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"106 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146111221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yu Zong,Nawei Zhang,Jason Lin,Zhizhong Li,Yuqiao Zou,Rohit Chaudhuri,Minkui Luo
Protein lysine methylation is a distinct class of post-translational modifications because it minimally alters the size and positive charge of the lysine side chain. In cellular contexts, the human genome encodes over 60 protein lysine methyltransferases (PKMTs), with the S-adenosyl-l-methionine (SAM) cofactor as the methyl donor, to modify thousands of lysine sites on histones and nonhistone targets in a highly orchestrated manner. The biological roles of protein lysine methylation are increasingly implicated in epigenetic regulation to define diverse cell fates, and their dysregulation is frequently associated with developmental abnormalities and various aspects of cancerous malignancy. However, it has been challenging to annotate the multiple upstream methyltransferase(s) in parallel from known methyllysine marks in the context of over 60 PKMT candidates with redundant and cell-type-dependent activities. We therefore envisioned the technology of Covalent Trapping of Protein Lysine Methyltransferases (CTPM) by assembling the ternary dead-end complex of PKMTs with substrate-cofactor surrogates. With SET-domain-containing PKMTs, the norleucine(Nle)-SAM pair was shown to be a robust structural motif to form such dead-end complexes, likely via harnessing the common feature of the transition state of PKMT-catalyzed lysine methylation. Our CTPM peptidic probes contain the Nle warhead in the place of substrate lysine, the photo-cross-linking residue in proximity of Nle, and the terminal biotin anchor for target enrichment. These CTPM probes, upon pairing with the SAM cofactor, show high efficiency in trapping the upstream PKMTs of the cognate histone and nonhistone substrates.
{"title":"Assembling Ternary Dead-End Complex for Covalent Trapping of Protein Lysine Methyltransferases","authors":"Yu Zong,Nawei Zhang,Jason Lin,Zhizhong Li,Yuqiao Zou,Rohit Chaudhuri,Minkui Luo","doi":"10.1021/jacs.5c14571","DOIUrl":"https://doi.org/10.1021/jacs.5c14571","url":null,"abstract":"Protein lysine methylation is a distinct class of post-translational modifications because it minimally alters the size and positive charge of the lysine side chain. In cellular contexts, the human genome encodes over 60 protein lysine methyltransferases (PKMTs), with the S-adenosyl-l-methionine (SAM) cofactor as the methyl donor, to modify thousands of lysine sites on histones and nonhistone targets in a highly orchestrated manner. The biological roles of protein lysine methylation are increasingly implicated in epigenetic regulation to define diverse cell fates, and their dysregulation is frequently associated with developmental abnormalities and various aspects of cancerous malignancy. However, it has been challenging to annotate the multiple upstream methyltransferase(s) in parallel from known methyllysine marks in the context of over 60 PKMT candidates with redundant and cell-type-dependent activities. We therefore envisioned the technology of Covalent Trapping of Protein Lysine Methyltransferases (CTPM) by assembling the ternary dead-end complex of PKMTs with substrate-cofactor surrogates. With SET-domain-containing PKMTs, the norleucine(Nle)-SAM pair was shown to be a robust structural motif to form such dead-end complexes, likely via harnessing the common feature of the transition state of PKMT-catalyzed lysine methylation. Our CTPM peptidic probes contain the Nle warhead in the place of substrate lysine, the photo-cross-linking residue in proximity of Nle, and the terminal biotin anchor for target enrichment. These CTPM probes, upon pairing with the SAM cofactor, show high efficiency in trapping the upstream PKMTs of the cognate histone and nonhistone substrates.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"1 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146111223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Emilee E. Shine,Julie S. Valastyan,Vanessa Y. Ying,Jonathan Z. Huang,Mohammad R. Seyedsayamdost,Bonnie L. Bassler
Bacteria use small molecules to orchestrate collective behaviors in a process called quorum sensing (QS), which relies on the production, release, and group-wide detection of extracellular signal molecules referred to as autoinducers. One QS autoinducer, termed AI-2, is broadly used for interspecies bacterial communication, including in the mammalian gut. AI-2 consists of a family of interconverting compounds and adducts originating from 4,5-dihydroxy-2,3-pentanedione. This complex speciation, coupled with the inherent instability of AI-2 congeners, have complicated isolation efforts. It has been known that mammalian epithelial cells produce an AI-2 mimic to which bacteria respond. However, the identity of the AI-2 mimic has remained elusive, presumably due to its instability, similar to that of known AI-2 compounds. Here, we developed a reactivity-based metabolomics approach to capture and identify a mammalian AI-2 mimic. Using a chemical strategy targeted at the α-diketone moiety of known AI-2s, we identify the unusual sugar l-xylosone, as well as the related metabolite l-xylulose, as AI-2 mimics. While l-xylulose is a common and naturally occurring sugar known in human metabolism, l-xylosone is a rare and highly reactive oxidation product. We established a facile synthetic route to access pure enantiomers of xylosone and confirmed that, like AI-2, the l-configuration is required for recognition by the bacterial AI-2 receptor, LuxP, whereas d-xylosone is inactive. l-xylosone is new to the human metabolome, suggesting that other chemically reactive small molecules that mediate host–microbe interactions await discovery. The identification of l-xylosone expands the AI-2 family of molecules and adds a new word to the lexicon of host–bacterial interactions.
{"title":"Discovery of a Human Metabolite That Mimics the Bacterial Quorum-Sensing Autoinducer AI-2","authors":"Emilee E. Shine,Julie S. Valastyan,Vanessa Y. Ying,Jonathan Z. Huang,Mohammad R. Seyedsayamdost,Bonnie L. Bassler","doi":"10.1021/jacs.5c18527","DOIUrl":"https://doi.org/10.1021/jacs.5c18527","url":null,"abstract":"Bacteria use small molecules to orchestrate collective behaviors in a process called quorum sensing (QS), which relies on the production, release, and group-wide detection of extracellular signal molecules referred to as autoinducers. One QS autoinducer, termed AI-2, is broadly used for interspecies bacterial communication, including in the mammalian gut. AI-2 consists of a family of interconverting compounds and adducts originating from 4,5-dihydroxy-2,3-pentanedione. This complex speciation, coupled with the inherent instability of AI-2 congeners, have complicated isolation efforts. It has been known that mammalian epithelial cells produce an AI-2 mimic to which bacteria respond. However, the identity of the AI-2 mimic has remained elusive, presumably due to its instability, similar to that of known AI-2 compounds. Here, we developed a reactivity-based metabolomics approach to capture and identify a mammalian AI-2 mimic. Using a chemical strategy targeted at the α-diketone moiety of known AI-2s, we identify the unusual sugar l-xylosone, as well as the related metabolite l-xylulose, as AI-2 mimics. While l-xylulose is a common and naturally occurring sugar known in human metabolism, l-xylosone is a rare and highly reactive oxidation product. We established a facile synthetic route to access pure enantiomers of xylosone and confirmed that, like AI-2, the l-configuration is required for recognition by the bacterial AI-2 receptor, LuxP, whereas d-xylosone is inactive. l-xylosone is new to the human metabolome, suggesting that other chemically reactive small molecules that mediate host–microbe interactions await discovery. The identification of l-xylosone expands the AI-2 family of molecules and adds a new word to the lexicon of host–bacterial interactions.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"8 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146111226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dynamic covalent bonds (DCBs) enable reversible bond formation/cleavage, offering exciting possibilities for smart and adaptive materials, yet challenges such as slow kinetics and stringent conditions required for the reverse reaction currently hinder their broader use. We present a novel C-N σ-bond with exceptional reversibility and ultrafast kinetics (t1/2 = 200 ms) across diverse primary aliphatic amine substrates, occurring spontaneously under ambient conditions without catalysts or external energy input, which is enabled by remarkably low activation barriers and near-equilibrium energetics. We showcase this transformative DCB's versatility in reversible gas-fixation, programmable transamination, and construct the first reversible chemical probes for real-time quantitative tracking of spatiotemporal histamine dynamics in live cells and in vivo within the brain under inflammatory pathology. This work redefines C-N σ-bonds as dynamic linkages, opening avenues for innovation in organic chemistry, adaptive materials, and dynamic biosystems.
{"title":"De Novo Labile C-N Bonds Enable Dynamic Covalent Chemistry and Reversible Bioimaging.","authors":"Chenming Chan, Yating Wang, Jingjing Wan, Yujie Han, Zhaoli Xue, Yang Tian, Qi-Wei Zhang","doi":"10.1021/jacs.5c16437","DOIUrl":"https://doi.org/10.1021/jacs.5c16437","url":null,"abstract":"<p><p>Dynamic covalent bonds (DCBs) enable reversible bond formation/cleavage, offering exciting possibilities for smart and adaptive materials, yet challenges such as slow kinetics and stringent conditions required for the reverse reaction currently hinder their broader use. We present a novel C-N σ-bond with exceptional reversibility and ultrafast kinetics (<i>t</i><sub>1/2</sub> = 200 ms) across diverse primary aliphatic amine substrates, occurring spontaneously under ambient conditions without catalysts or external energy input, which is enabled by remarkably low activation barriers and near-equilibrium energetics. We showcase this transformative DCB's versatility in reversible gas-fixation, programmable transamination, and construct the first reversible chemical probes for real-time quantitative tracking of spatiotemporal histamine dynamics in live cells and in vivo within the brain under inflammatory pathology. This work redefines C-N σ-bonds as dynamic linkages, opening avenues for innovation in organic chemistry, adaptive materials, and dynamic biosystems.</p>","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":" ","pages":""},"PeriodicalIF":15.6,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146117067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Some semiconductor materials exhibit axis-dependent conduction polarity (ADCP), where carrier transport is dominated by electrons along one crystallographic axis and holes along another. This unconventional transport behavior enables transverse thermoelectricity and other functionalities that are inaccessible in conventional isotropic/unipolar semiconductors. However, only a few ADCP materials have been identified, largely because the underlying electronic design principles have remained unclear. Here, we establish a quantitative framework that defines the electronic conditions required for ADCP to emerge and remain robust. Using a minimal two-band tight-binding model, we clarify that ADCP requires two key electronic conditions: a sufficiently small band gap that enables simultaneous electron–hole transport and strong anisotropy in carrier effective masses that causes their transport contributions to differ between axes. These parameters define a chemical-potential window in which axis-resolved Seebeck coefficients take opposite signs, identifying narrow-gap semiconductors and semimetals with anisotropic band edges as prime ADCP candidates. Guided by these criteria, we conduct a first-principles screening of 4282 anisotropic narrow-gap semiconductors and metals and identify 361 ADCP materials, which are predominantly found among chalcogenides, pnictides, and tetrel-based compounds, including 57 potential transverse thermoelectrics. Analysis of two representative materials, AlReGe and ZrSe3, reveals that ADCP originates from anisotropic band-edge states derived from low-dimensional bonding networks, resulting in spatially separated electron and hole transport on different crystal sublattices. These results provide chemically intuitive design rules for ADCP materials and establish a comprehensive data set for accelerating the development of transverse thermoelectrics and other next-generation electronic devices.
{"title":"Axis-Dependent Conduction Polarity: Design Principles and High-Throughput Discovery of Transverse Thermoelectrics","authors":"Zan Yang,Xinyi He,Hidetomo Usui,Toshio Kamiya,Takayoshi Katase","doi":"10.1021/jacs.5c22733","DOIUrl":"https://doi.org/10.1021/jacs.5c22733","url":null,"abstract":"Some semiconductor materials exhibit axis-dependent conduction polarity (ADCP), where carrier transport is dominated by electrons along one crystallographic axis and holes along another. This unconventional transport behavior enables transverse thermoelectricity and other functionalities that are inaccessible in conventional isotropic/unipolar semiconductors. However, only a few ADCP materials have been identified, largely because the underlying electronic design principles have remained unclear. Here, we establish a quantitative framework that defines the electronic conditions required for ADCP to emerge and remain robust. Using a minimal two-band tight-binding model, we clarify that ADCP requires two key electronic conditions: a sufficiently small band gap that enables simultaneous electron–hole transport and strong anisotropy in carrier effective masses that causes their transport contributions to differ between axes. These parameters define a chemical-potential window in which axis-resolved Seebeck coefficients take opposite signs, identifying narrow-gap semiconductors and semimetals with anisotropic band edges as prime ADCP candidates. Guided by these criteria, we conduct a first-principles screening of 4282 anisotropic narrow-gap semiconductors and metals and identify 361 ADCP materials, which are predominantly found among chalcogenides, pnictides, and tetrel-based compounds, including 57 potential transverse thermoelectrics. Analysis of two representative materials, AlReGe and ZrSe3, reveals that ADCP originates from anisotropic band-edge states derived from low-dimensional bonding networks, resulting in spatially separated electron and hole transport on different crystal sublattices. These results provide chemically intuitive design rules for ADCP materials and establish a comprehensive data set for accelerating the development of transverse thermoelectrics and other next-generation electronic devices.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"88 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146111198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shilong Fu,Bowen Sha,Asvin Sajeev,Ming Li,Thijs J. H. Vlugt,Othonas A. Moultos,Wiebren de Jong,Ruud Kortlever
Electrochemical CO2 reduction to CO offers a sustainable route for converting CO2 into value-added chemicals and fuels. However, CO2 streams derived from industrial sources often contain SO2 impurities that severely poison conventional metal-based catalysts. Here, we report a nitrogen-doped carbon catalyst that exhibits pronounced tolerance and stability for CO2-to-CO conversion in the presence of SO2 (100–10,000 ppm). The catalyst maintains over 90% Faradaic efficiency toward CO during 8 h of electrolysis at −1.0 V vs RHE with 100 ppm of SO2, whereas Ag foil electrodes undergo rapid deactivation. Density functional theory calculations combined with surface analyses indicate that weak SO2 adsorption and the absence of stable sulfur accumulation on nitrogen-doped carbon strengthen its resistance to impurity-induced deactivation, in contrast to Ag catalysts that form Ag2S. Gas-fed tests in a membrane electrode assembly (MEA) electrolyzer further confirm that nitrogen-doped carbon sustains high CO selectivity at elevated current densities, while Ag nanoparticles suffer irreversible sulfur poisoning. These results demonstrate that nitrogen-doped carbon is intrinsically resistant to SO2-induced deactivation and highlight its potential as a robust catalyst for CO2 electroreduction under impurity-containing conditions.
电化学CO2还原为CO提供了将CO2转化为增值化学品和燃料的可持续途径。然而，来自工业来源的二氧化碳流通常含有SO2杂质，严重毒害传统的金属基催化剂。在这里，我们报道了一种氮掺杂碳催化剂，在SO2 （100-10,000 ppm）存在下，对co2到co的转化表现出明显的耐受性和稳定性。在−1.0 V vs RHE和100 ppm SO2条件下电解8 h，催化剂对CO的法拉第效率保持在90%以上，而银箔电极则快速失活。密度泛函理论计算结合表面分析表明，与形成Ag2S的Ag催化剂相比，氮掺杂碳对SO2的弱吸附和不存在稳定的硫积累增强了其对杂质诱导失活的抗性。在膜电极组件（MEA）电解槽中的气供测试进一步证实，氮掺杂碳在高电流密度下保持高CO选择性，而银纳米颗粒则遭受不可逆的硫中毒。这些结果表明，氮掺杂碳本质上抵抗二氧化硫诱导的失活，并突出了其作为含杂质条件下CO2电还原催化剂的潜力。
{"title":"Electrochemical CO2 Reduction in the Presence of SO2 Impurities on a Nitrogen-Doped Carbon Electrocatalyst","authors":"Shilong Fu,Bowen Sha,Asvin Sajeev,Ming Li,Thijs J. H. Vlugt,Othonas A. Moultos,Wiebren de Jong,Ruud Kortlever","doi":"10.1021/jacs.5c11790","DOIUrl":"https://doi.org/10.1021/jacs.5c11790","url":null,"abstract":"Electrochemical CO2 reduction to CO offers a sustainable route for converting CO2 into value-added chemicals and fuels. However, CO2 streams derived from industrial sources often contain SO2 impurities that severely poison conventional metal-based catalysts. Here, we report a nitrogen-doped carbon catalyst that exhibits pronounced tolerance and stability for CO2-to-CO conversion in the presence of SO2 (100–10,000 ppm). The catalyst maintains over 90% Faradaic efficiency toward CO during 8 h of electrolysis at −1.0 V vs RHE with 100 ppm of SO2, whereas Ag foil electrodes undergo rapid deactivation. Density functional theory calculations combined with surface analyses indicate that weak SO2 adsorption and the absence of stable sulfur accumulation on nitrogen-doped carbon strengthen its resistance to impurity-induced deactivation, in contrast to Ag catalysts that form Ag2S. Gas-fed tests in a membrane electrode assembly (MEA) electrolyzer further confirm that nitrogen-doped carbon sustains high CO selectivity at elevated current densities, while Ag nanoparticles suffer irreversible sulfur poisoning. These results demonstrate that nitrogen-doped carbon is intrinsically resistant to SO2-induced deactivation and highlight its potential as a robust catalyst for CO2 electroreduction under impurity-containing conditions.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"88 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146111224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Molecular photoswitching in the red and near-infrared (NIR) region is highly sought after for applications in biological systems, optoelectronic devices, and functional materials where low-energy light minimizes photodamage and enables deep-tissue penetration. However, developing photoswitches that simultaneously achieve long-wavelength responsiveness with robust thermal bistability and high quantum efficiency remains a formidable challenge. Here, we report an intrinsic thermo-bistable, red-light-responsive (605 nm/730 nm) photochromic motif based on a perylene bisimide (PBI) scaffold, which further enables an unprecedented sensitized NIR (808 nm/730 nm) photoisomerization through a triplet pathway. Rational side-chain engineering with aryl substituents of distinct aromaticity and electronic character finely tunes the transition-state energy barrier (ΔG‡ = 45.07 kcal mol–1), leading to exceptional thermal stability and a long-lived closed isomer. Further molecular engineering of PBI-based photoswitches also delivers high photoisomerization quantum yield, bright fluorescence, and near-quantitative photoconversion efficiency. This work provides a new photochromic motif that boosts the overall photochemical/thermal performances of molecular photoswitching at the red-light end, thereby enriching the structural and functional landscape of a high-performance photoswitching system. Demonstrations in dynamic cell-membrane imaging further highlight the potential of these PBI-based photoswitches as powerful photochemical platforms for advanced biomedical and optoelectronic applications.
{"title":"Thermo-Bistable Red and Sensitized Near-Infrared Photoswitches","authors":"Zhiwei Zhang,Zhubin Hu,Lei Huang,Huichao Guo,Jinghong Dai,Long Deng,Guining Gong,Tong Xia,Ruijia Sun,Botao Ji,Wei-Hong Zhu,Junji Zhang,He Tian","doi":"10.1021/jacs.5c20020","DOIUrl":"https://doi.org/10.1021/jacs.5c20020","url":null,"abstract":"Molecular photoswitching in the red and near-infrared (NIR) region is highly sought after for applications in biological systems, optoelectronic devices, and functional materials where low-energy light minimizes photodamage and enables deep-tissue penetration. However, developing photoswitches that simultaneously achieve long-wavelength responsiveness with robust thermal bistability and high quantum efficiency remains a formidable challenge. Here, we report an intrinsic thermo-bistable, red-light-responsive (605 nm/730 nm) photochromic motif based on a perylene bisimide (PBI) scaffold, which further enables an unprecedented sensitized NIR (808 nm/730 nm) photoisomerization through a triplet pathway. Rational side-chain engineering with aryl substituents of distinct aromaticity and electronic character finely tunes the transition-state energy barrier (ΔG‡ = 45.07 kcal mol–1), leading to exceptional thermal stability and a long-lived closed isomer. Further molecular engineering of PBI-based photoswitches also delivers high photoisomerization quantum yield, bright fluorescence, and near-quantitative photoconversion efficiency. This work provides a new photochromic motif that boosts the overall photochemical/thermal performances of molecular photoswitching at the red-light end, thereby enriching the structural and functional landscape of a high-performance photoswitching system. Demonstrations in dynamic cell-membrane imaging further highlight the potential of these PBI-based photoswitches as powerful photochemical platforms for advanced biomedical and optoelectronic applications.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"75 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146111219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tristan Georges,Ran Wei,X. Ray Cowen,Likai Zheng,Michael Grätzel,Lyndon Emsley
Understanding and controlling surface structure at the atomic scale is essential in functional materials, yet direct and selective surface characterization in such systems remains a challenge. Here a broadly applicable strategy for surface-only solid-state NMR enabled by dynamic nuclear polarization (DNP) is introduced. The method exploits partially deuterated vitrified solvents as proximity “probe” molecules and 2H-based dipolar dephasing to filter out signals from the bulk, thereby providing clear detection of nuclei located exclusively in the first one or two atomic layers at the surface (without 1H–2H exchange). Implemented through a 1H–X{2H} CP-REDOR scheme, this approach allows the detection of X through the 2H–X dipolar couplings, which are almost an order of magnitude lower than their 1H–X counterparts, thus providing unprecedented surface selectivity. The applicability of the new method is demonstrated on several compounds including core–shell nanocrystalline hydroxyapatite, tin dioxide, silica, as well as a passivated hybrid perovskite, and surface sites are resolved that would otherwise have been obscured by the bulk signals. Quantitative analysis of the dephasing curves allows interfacial distance measurements to the solvent. This 2H-dephasing DNP approach establishes a versatile platform for the atomic-scale characterization of functional surfaces in both inorganic materials and proton-rich nanomaterials.
{"title":"Surface-Only Nuclear Magnetic Resonance Spectroscopy by Dynamic Nuclear Polarization and 2H-Dephasing","authors":"Tristan Georges,Ran Wei,X. Ray Cowen,Likai Zheng,Michael Grätzel,Lyndon Emsley","doi":"10.1021/jacs.5c21534","DOIUrl":"https://doi.org/10.1021/jacs.5c21534","url":null,"abstract":"Understanding and controlling surface structure at the atomic scale is essential in functional materials, yet direct and selective surface characterization in such systems remains a challenge. Here a broadly applicable strategy for surface-only solid-state NMR enabled by dynamic nuclear polarization (DNP) is introduced. The method exploits partially deuterated vitrified solvents as proximity “probe” molecules and 2H-based dipolar dephasing to filter out signals from the bulk, thereby providing clear detection of nuclei located exclusively in the first one or two atomic layers at the surface (without 1H–2H exchange). Implemented through a 1H–X{2H} CP-REDOR scheme, this approach allows the detection of X through the 2H–X dipolar couplings, which are almost an order of magnitude lower than their 1H–X counterparts, thus providing unprecedented surface selectivity. The applicability of the new method is demonstrated on several compounds including core–shell nanocrystalline hydroxyapatite, tin dioxide, silica, as well as a passivated hybrid perovskite, and surface sites are resolved that would otherwise have been obscured by the bulk signals. Quantitative analysis of the dephasing curves allows interfacial distance measurements to the solvent. This 2H-dephasing DNP approach establishes a versatile platform for the atomic-scale characterization of functional surfaces in both inorganic materials and proton-rich nanomaterials.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"1 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146111199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alternating current (AC) electrolysis furnishes a dynamic electric field with tunable frequency, duty ratio, and waveform, features that have recently conferred distinct advantages in organic electrosynthesis. In this work, we introduce an unsymmetrical AC waveform-driven Cu-catalyzed oxidative strategy that employs available β-keto carbonyls, alkenes or alkynes to access valuable 5,5-spirocyclic and E-type alkene scaffolds via intra- and intermolecular carbon–oxygenation. Under two distinct waveforms, the reactions proceed smoothly via a Cu-bound radical and nucleophilic addition pathway, respectively. Electron paramagnetic resonance (EPR) studies demonstrate that unsymmetrical AC waveforms maintain a high-concentration dynamic equilibrium of copper intermediates within their respective reaction environments. These findings broaden the scope of AC electrosynthesis and illustrate how waveform design can be leveraged to direct reactivity in challenging bond-forming cascades.
{"title":"Waveform-Enhanced Alternating Current Electrocatalysis Enables Cu-Catalyzed Carbon–Oxygenation of β-Keto Carbonyls with Alkenes and Alkynes","authors":"Qinghong Yang,Linpu Zhou,Bufan Dang,Yeran Liu,Jianxing Wang,Xin Wang,Wei Ding,Zhiqiang Zhang,Yiheng Guo,Jiaxin Yuan,Heng Zhang,Hong Yi,Li Zeng,Aiwen Lei","doi":"10.1021/jacs.5c19029","DOIUrl":"https://doi.org/10.1021/jacs.5c19029","url":null,"abstract":"Alternating current (AC) electrolysis furnishes a dynamic electric field with tunable frequency, duty ratio, and waveform, features that have recently conferred distinct advantages in organic electrosynthesis. In this work, we introduce an unsymmetrical AC waveform-driven Cu-catalyzed oxidative strategy that employs available β-keto carbonyls, alkenes or alkynes to access valuable 5,5-spirocyclic and E-type alkene scaffolds via intra- and intermolecular carbon–oxygenation. Under two distinct waveforms, the reactions proceed smoothly via a Cu-bound radical and nucleophilic addition pathway, respectively. Electron paramagnetic resonance (EPR) studies demonstrate that unsymmetrical AC waveforms maintain a high-concentration dynamic equilibrium of copper intermediates within their respective reaction environments. These findings broaden the scope of AC electrosynthesis and illustrate how waveform design can be leveraged to direct reactivity in challenging bond-forming cascades.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"62 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146111220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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